Agricultural drain water

Johnson ML, Salveson A, Holmes L, et al. 1998. Environmental estrogens in agricultural drain water from the Central Valley of California. Bull Environ Contam Toxicol 60 609-614. 

Wu L, Van Mantgem PJ, Guo X. 1996. Effects of forage plant and field legume species on soil selenium redistribution, leaching, and bioextraction in soils contaminated by agricultural drain water sediment. Arch Environ Contam Toxicol 31 329-338. 

Selenium accumulation in agricultural drainage waters and basins has been documented in the western United States, particularly in California. The problem was first discovered in the Kesterson Wildlife Refuge in the San Joaquin Valley of California. In 1975, the U.S. Bureau of Reclamation finished construction of an 85-mile subsurface agricultural water drain that terminated in a series of evaporation... 

In kaolin (clay) processing, sulfur dioxide reduces colored impurities, eg, iron compounds. In the bromine industry, sulfur dioxide is used as an antioxidant in spent brine to be reinjected underground. In agriculture, especially in California, sulfur dioxide is used to increase water penetration and the avadabiHty of soil nutrients by virtue of its abiHty to acidulate saline—alkaH soils (327). It is also usefiil for cleaning ferric and manganese oxide deposits from tile drains (328). 

Two major rivers in California influenced by a Mediterranean climate are the Sacramento River and the San Joaquin River. The Sacramento River drains 72,132 km with a relief of 4,317 m. Mean discharge is 650 m /s with peak flows in the winter and early spring and with minimum flows in the late summer and early fall. The San Joaquin River drains 83,409 km with a relief of 4,418 m. Mean discharge is 130 m /s with peak flows in spring and low flows in late summer and fall. Population density is 24 people/km in the Sacramento River basin and 29 people/km in the San Joaquin basin. Agriculture in the Central Valley of California that encompasses parts of both basins is the primary user of water in both basins [1]. 

Rekolainen S. 1988. Occurrence and leaching of pesticides in waters draining from agricultural land. 

Among these regions is the Ebro River, the Spain s most voluminous and important river in the country. With 910 km, the river accounts for approximately 6% of all riverine waters entering the Mediterranean and drains approximately one-sixth of the Iberian Peninsula, including important urban and industrial areas [3]. But because it is highly exploited by industrial and agricultural activities, the Ebro River basin is the focus of several scientific studies [4-10]. 

This high agriculture activity compromises the chemical and ecological status of the Ebro delta. Pesticides used in the area migrate into the delta building up, together with the pollution produced by some industries, a contamination that can be dangerous to its both fauna and flora, and this contamination increases when water from the rice fields is drained into the delta [17]. 

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